Process for cracking oils



Dee:a 8, 1931. H. J. HALLE PROCESS FOR CRACKNG OILS 4 Sheets-Sheet lFiled sept. 22, 1924 JHM/e mi@ My.

ttot nu DeC- 8 193f H. J. HALLE 1,835,77

PROCESS FOR CRCKING OILS Filed sept. 22, 1924 4 Sheets-sheet 2 wm/lf Dea8, 1931. H, ,j HALLE 1,835,774

PROCESS FOR CRACKING vOILS Filed Sept. 22, 1924 4 Sheets-Sheet 3 I l l 5Dec. s, v1931.4 H, J HALLE 1,835,774

y PROCESS FOR CRACKING OILS Filed Sept. 22, 1924 4 Sheets-Sheet 45mm/wai IZ da/le Patented Dec. 8, 1931 ASTATES PATENT OFFICE HIBAM J.HALLE, OF NEW YORK, N. Y., ASSIGN'OII, TO UNIVERSAL OIL PRODUCTSCOMPANY, OF CHICAGO, ILLINOIS, A CORPORATION F SOUTH DAKOTA PROCESS FORCRACKING OILS Application led September 22, 1924. Serial No. 739,138.

The invention relates to improvements in a process for the conversion ofhydrocarbon oils.

It isfan object of the invention to provide a an oil conversion processutilizing a battery l@ and to reduce costs in plant construction,

operation and generally improve the results.

With the foregoing conception in mind, one of the broad features of theinvention consists in returning reflux condensate obtained from thecondensation of vapors produced in a battery of stills to at least twoof said stills by means of a single pump for rapidly recycling saidcondensate through said stills in opposition to thefrictional resistanceof oil passing therethrough.

In a more specific aspect, the present invention contemplates a batteryof stills having suitable reflux condensing means for separating theinsufficiently cracked vapors from said stills from the low boilingpoint oils, with a single refluxfeeding pump to which condensate isintroduced adapted to feed through suitable feeding lines the desiredquantity of reflux condensate with or without charging stock to two ormore stills of the battery, so that said condensate with.

or without mixed charging stock is rapidly circulated' through thestills to undergo further treatment therein.

The invention is particularly applicable to the batteryv of stills ofthe tube and chamber type, that is, each still in the battery comprisinga continuous coil through which the oil is rapidly passed and anenlarged conversion chamber where said oil completes its reaction. thevapors from this chamber being subjected to al reflux condensing actionwhile the residue is withdrawn. The invention. however, is clearlyapplicable to other types of stills, as will be clearly apparent fromthe following description.

It is a further object of the invention to provide an improved processfor supplying charging stock to the different stills constituting thebattery by feeding to the inlet of two or more of the stills separatestreams of charging stock from a single pump or other mechanicalpressure applying device.

` It is a still further object of the invention to provide an improvedprocess for cracking oils utilizing a number of stills constituting abattery, in which one or more pumps can be utilized for feeding bothreflex condensate and charging stock to the various units in thebattery, to provide a process in which charging stock can be fed to oneor more of the dephlegmators, and this charging stock, together withreflux condensate returned to at least two of said units by a singlepump or other mechanical pressure applying device common to ysaid units.

In 'the accompanying drawings I have shown diagrammatically thepreferred embodiment of my invention, in which Figure 1 represents aview wherein a single charging pump is utilized for feeding raw oil to abattery of four units and a single reflux pump employed common to all ofsaid units.

In Figure 2 I have shown a modification of my invention where onecharging pump is common to the battery and two reflux pumps for feedingreflux condensate thereto.

In Figure 3 I have shown a modification wherein va ors from at least twostills enter a single re ux condenser and the reflux condensate fromthis condenser is circulated by a single pump to said stills.I

Figure 4 is an elevation, partly in section, of the structure shown kinFig. l and showing diagrammatic details of the furnace, conversionchamber, and dephlegrlator.

Figure 5 is an elevation of the structure shown in Fig. '3.

Referring -now more particularl to the drawings wherein like reference caracters indicate corresgpnding parts, thek reference character A inigure 1 designates a battery of stills, which may consist of two or moreseparate units. Four units are shown but this disclosure is merely forthe purpose of illustration and any number can be employed. In thisdisclosure as each unit is of the same specific construction, adescription of one will suffice for all. Each unit embodies a furnacestructure 1 having a combustion chamber 2 heated by gases or oil fromthe burners 3, with a series of cracking tubes 4 disposed on one side ofa bridge wall separating said tubes from the combustion chamber, throughwhich tubes the oil is circulated under a pump pressure in a manner tobe hereinafter described. A transfer lineV 5 conducts the oil from saidheating tubes to an enlarged chamber 6 where conversion occurs. Thischamber is shown as being insulated, but it could be otherwiseconstructed, if desired. It is-within the scope of this invention toapply heat to this chamber should this be found to be desirable.4 Thechamber is vertically disposed, is provided with a carbon dischargeopening 7 at its lower end and a series of independently controlledresidual drawofl' lines 8, by means of which liquid residuum may bewithdrawn from the system. A vapor transfer line 9 conducts the vaporsfrom the chamber 6 to a dephlegmator 10 to be now described. Thedephlegmator 10 may be of any approved construction.

For illustrating this invention, however, I have selecteda dephlevmatorhaving therein a series of pans or ba es 11 for retarding the passage ofvapors therethrough and in this de hlegmator I condense theinsufficient- 1y crac ed vapors, preferably by introducing theretocharging stock through a feeding line 12, or pressure distillate througha line 13. The condensed vapors pass through the line 14, and thecondensate from the dephlegmators of the battery flowing through thesaid lines 14 collect in a receiver 14 lcommon to two or more of thedephlegmators and from which receiver the condensate is fed-to theheating coil 4 in a manner to be later described.

The raw charging stock entering the system is fed to a single pump 15through an oil feeding line 15. From this pump a series of branch lineslead respectively to -each heating coil 4 and to each dephlegmator 10.'Ifhat is to say, a single feeding pump is utilized for feeding raw oilto each unit through a line 16, and overhead to each dephlegmatorthrough a line 12. In the disclosure of the invention as set forth inFigures 1 and 4, lines 12 and 16 lead from the pump 15, respectively tothe dephlegmator and the heating coil of each unit. Of course, as shownin the modification of the invention two or more feeding pumps may beemployed, if desirable.

The condensate in the receiver 14 common to two or more of thedephlegmators enters the pump 17, and from this pump the condensateflows through the lines 18 to each charging line, merging with the rawstock at the points X of each unit. It will be clearly seen that asingle pum receives condensate from a pluralit of ephlegmators and saidpump is utilize to feed the condensate to a plurality of cracking units.The pumps 17 may also be arranged in parallel if desired, so that if formechanical reasons one pump becomes inoperative the other pump can beutilized.

The uncondensed vapors from the dephlegmator 10 are discharged throughthe line 19 and pass through a condenser 20 where they are condensed andthe distillate collected in a receivingtank 21. An incondensable gasdischarge pipe 22 is provided with a valve 23 by means of which a va orpressure can be maintai-ned throughout t e system.

In operating the embodiment of the process as carried out in theapparatus shown in Figure 1, if a gas oil'is utilized the oil should beheated so that its transfer temperature approximates .85()o F. Apressure of upwards of 100 pounds per square inch can be maintainedythroughout the system by setting the vvalves 23. Differential pressuresmay, however, be maintained in different parts of the apparatus byoperating the valves 24, 25 and 26. For instance, a reduced pressure canbe maintained on the expansion chamber 6 or the expansion chamber 6 andthe coil 4 of each unit may be under a uniform pressure and a reducedpressure maintained in the dephlegmator 10 and the condenser 20. A

From the foregoing description of the process as carried out in theapparatus shown in Figure 1, it will be seen that a single charging pumpisA utilized for feeding the plurality of units constituting thebattery, and that a single refiux pump is also employed which is commonto all'of said units.

It will also be seen that the charging pump can feed a portion of thecharging stock to the top of each dephlegmatol` through the valvecontrolled llines 12 and a portion of the stockdirectly through thelines 16 to the cracking ,coils 4 or all of the stock can be fedoverhead or none overhead and all direct to the cracking coils. This`dispenses with a series of pumps and minimizes the mechanicaldifficulties encountered in the use of a battery of stills. Itfurthermore permits all of the units to be operated under the sameuniform conditions resulting in the production of a uniform distillate.

In thecmbodiment of the invention as illustrated in Figure 2 thecracking apparatus employed is the same as heretofore employed in thediscussion of Figure 1. That is to say each unit in the battery comrises the heating-coil 4, theconversion cham r 6, and a dephlegmator 10.In this embodiment of the invention, however, a single pump is notcommon to all of the dephlegmators 10 of the battery. As shown in Figure2, the dephlegmators B and C discharged refiux condensate through thelines 14 to a common receiver D, and from this receiver the reflux isfed to a pump E common to the two units in the battery which feed vaporsto said dephlegmators B and C. The reflux is fed by said pump throughthe lines F and G to the heating coils 4. In this embodiment of theinvention a single charging pump 15 is employed, although obviously twoof these pumps may be used, if desirable, in which instance each pumpwould feed to two yunits of the battery. The same operating pressuresand temperatures can be maintained in carrying out this process ashereinbefore set forth in the description of the process as carried outby the apparatus illustrated in Figure 1.

In Figure 3 of the drawings I have shown a modilication of thisinvention wherein an independent dephlegmator 30 need not be utilizedfor each unit ofthe battery. That is to say, in this embodiment of theinventionone or more dephlegmators can be used for the entire battery ofstills. In the disclosure I have shown a single enlarged dephlegmator 30for each two units of the battery. The vapors from the conversionchambers 6 in the construction .hereinbefore described pass through thevapor lines 9 to said dephlegmator which is cooled by oil fed overheadthrough the charging line 12, as hereinbefore described. Of course, thisdephlegmator may 'otherwise be cooled, if desired. In this embodiment ofthe invention the reflux condensate from the enlarged dephlegmator 30collects in the leg 31 and from this leg it is fed by a pump 32 to thelines 33 and 34 to the two units fromvwhich the dephlegmator 30 receivesits vapors. That is to say the condensate from the single dephlegmatorreceiving vapors from the two units is returned to these two units underthe pressure by the single pump 32 and cycled therethrough. In thisembodiment of the invention I may also feed charging stock partiallyoverhead through the line 12 and partially direct to the cracking coils4 through the lines 16 to each pair of units by a-single pump 35. Ofcourse, all the charging stock can be fed overhead to the dephlegmator,30, b this pump or no charging stock need be fe overhead and., all ofthe raw charging stock may be' fed directly through the lines 16 to thetwo heating coils. From this disclosure it will be seen that onecharging pump for raw charging stock is utilized for each pair of units.It will be clearly understood, however. that the four or more units maybe combined in the manner just described in dealing with the two units,that is to say, a single dephlegmator may be employed `for a number ofunits and one or more pumps utilized for feeding the reflux to thecracking coils of said units. Furthermore, a single charging pump may beutilized for any number of units depending upon the capacity of theunits and size of the pump. In the operation of the various embodimentsof this invention, the vapors discharged from the reflux condenser areall condensed in the final condenser, save the incondensible gases, andsuperatmospheric pressures may be maintained throughout the system bythe control of these gases or interposed valves may be placed betweenthe different parts of each unit, whereby differential pressure may bemaintained. The temperature to which the oil passingzthrou h the heatingcoils is subjected may vary, ut I propose to employ a temperaturesuilicient to bring the oil to a conversion heat and with a gasoil froma mid-continent field a transfer temperature of about 850 degrees F. hasbeen found desirable.

In the present disclosure, I have shown a tube and chamber type of stillcapable of continuous operation wherein residual oil may be dischargedfrom the expansion chambers without being again admitted to the crackingcoils wherein the reflux condensate is continuously recycled forrecracking. I wish it to be understood, however, that any well knowntype of still can be utilized in this process. That is to say,I canemploy a batch still or any still utilizing a dephlegmator.

Having thus described my invention, what I claim is:

1. An improvement in the art of pressure distillation, comprisingcontinuously feeding a stream ofcharging oil to a plurality of separatestills maintained' undier cracking conditions of temperature andpressure, each of the stills including a heating zone through which arestricted stream of oil is passed, and an enlarged reaction zone whereconversion of the oil occurs, in discharging residuum from each of saidenlarged reaction zones without retreatment,in subjecting the vaporsdischarged from each reaction zone to ydephlegmation commingling thereflux condensates resulting from the dephlegmation of the vaporsdischarged from each reaction zone and in introducing under an appliedmechanical pressure saidcommingled reflux condensate moving in separatestreams to the o1l stream passing to each of said stills.

2.- An improvement in the art of pressure I distillation comprisingmaintaining oil in a plurality of separate stills under crackingconditions of temperature and pressure, in discharging the vaporsgenerated in each still to a dephlegmating zone, in collecting in a poolreflux condensate formed in a plurality of said dephlegmating zones,and-1n introducing said condensate in separate streams to each of saidstills for retreatment therein.

3. An improvement in the art of pressure distillation of hydrocarbonoils, comprising maintainingv oil in a plurality of separate stillsunder cracking conditions of temper? ature and pressure, 1n subjectingthe vapors generated 1n each still to an independent refluxcondensation, in collecting the reflux condensate from a plurality ofsaid stills in a common receiver, and in forcing such condensate undermechanical pressure in streams, one of which passes to each of saidstills for retreatment therein.

4. An improvement in the art of pressure distillation, comprisingsubjecting oil to cracking conditions of temperature and pressure in aplurality of separate stills, in each of which stills avstream of oil iscontinuously advanced through a heating zone and thence admitted to anenlarged reaction zone, in removing vapors from each of said reactionzones, in subjecting such vapors to reflux condensation in separatedephlegmating zones, in collecting the condensate from saiddephlegmating zones in a common body, in introducing such condensate toeach still by forcingthe same in separate streams, one stream mergingwith each stream of oil to undergo conversion in each cracking still.

In testimony whereof I' aix my signature.

HIRAM J. HALLE.

